Variable displacement pump



D 1941- A. J. GRANBERG VARIABLE DISPLACEMENT PUMP Filed June 5, 1939 INVENTORT ALBERT J. GRANBERG.

BY 22% A RNEYS.

Patented Dec. 16, 1941 UNITED STATES, PATENT OFFICE vmmnm msrmcmuau'r rum Albert'J. Granberg, Berkeley, Calm, assignm- .to

Granberg Equipment, Inc.,

rnia

a corporation of Calilo Application June 5, 1939, Serial No. 277,394 (].103-120) Claims.

iable displacement pump ,whose output can be changed while running; to provide a combination of pumps wherein a variable output is obtained; to provide apump which is ideally adapted for the supply of fuel .to oil burners or the like; and to provide asimple and efficient variable displacement pump.

Other objects of my invention will be apparent or will be specifically pointed out in the description forming a part of this specification, .but I do not limit myself to the embodiment of the invention herein described, as various forms may be adopted within the scope of the claims.

Referring to the drawing:

Fig. 1 is a longitudinal sectional view of one form of variable displacement pump of my invention as attachedto a main supply pump.

Fig. 2 is a sectional view, taken as indicated by the line 2-2 in Fig. 1.

Fig. 3 is a cross-sectional view', taken as indi cated by the line 3-3 in Fig. 2.

Fig. 4 is a cross-sectional view, taken as indicated by the line 4-4 in Fig. 2.

Fig. 5 is apartial sectional view, similar to Fig. 4, showing the rotors in non-pumping position.

Fig. 6 is a partial longitudinal sectional view, showing the means for changing the output or the pump.

Referring directly to the drawing for a more detailed description of my invention, a casing l is provided with a cylindrical chamber 2 in which is mounted a cup-shaped rotor 3. The base plate 4 of this rotor is attached to a drive shaft 5.

In Fig. l I haveshown the pump of my invention attached to a. second pump 6, the end wall 1 of the second pump 6 being used as a mounting plate for the variable displacement pump. Pump 6 may be of any convenient type such as, for example, a gear pump driven by a shaft 1 and having a capacity at least equal to the maximum capacity of the attached variable displacement pump. The variable displacement pump is driven Emeryville, Calif from main shaft I of thegear pump by means of coupling 9 interlocking main shaft 1 and variabledisplacement pump shaft 5. .The use of thegear pump will be explained later, and inasmuch as the exact mechanism of thegear pumpis of no consequence to the present invention, no further reference to the detailed construction thereof will i be made.

Returning, therefore. to the construction of the variable displacement pump, cup 3 is shaped to fit the inner surface of side walls In of the cup, and an oil seal is provided therebetween. End plate II of the variable displacement pump fits over casing I and may be used to hold the variable displacement pump against end wall 1 of the main pump. End plate I I is provided with 1 oppositely disposed inlet and outlet ports I2 and I4 opening into the pump chamber l5 in the cup 3.

Journaled onend plate ll is a driven membershaft l6 extending toward pump chamber I5 to terminate therein as'an eccentric ll. The

axis of driven member shaft I6 is parallel to, but offset from, the axis of main shaft 5, but the eccentric l'l, forming a prolongation of shaft I 6, is so proportioned that when shaft I6 is turned to one position the eccentric end I! will be coaxial with the shaft 5, and therefrom is at maximum eccentricity with relation to shaft 5.

Mounted on eccentric ll, within chamber I5,

-is a driven cylinder I8 which extends from'base plate 4 of the cup-shaped rotor 3 to end plate II. The driven cylinder, however, is of lesser diameter than the diameter of pump chamber l5, so that pump chamber I5 is not completely filled. The diameter of driven cylinder l8, however, is such that when the'driven member shaft I6 is turned to provide maximum eccentricity of eccentric I! with relation to shaft 5, the periphery of driven cylinder l8 will closely approach'the inner walls of cup 3, and when shaft I6 is turned so that the eccentric I1 is coaxial with shaft 5 the driven cylinder It will also be coaxial with shaft 5, with the width of the pump chamber the same all around the driven cylinder.

' In order to provide a pumping action, driven cylinder I8 is provided with radially extending vanes 20 movable in slots 20' whichare formed in the base plate 4 for the purpose. While I have shown four such vanes, it will be obvious to those skilled in the art that more or less may be used. One of the vanes, 2|, known as the driving vane, differs from the remainder of the vanes in that it is provided with asemi-cylindrical end 22 which fits into a, semi-cylindrical slot 23 cut into the inner surface of the side walls of cup 3.

' Vanes 20 slide in slots 20' and are forced outwardly against the inner surface of the side walls of cup 3 by means of a single resilient ring 24 which presses outwardly against all of the vanes. Resilient ring 24 is positioned within a spring cavity 25 on the outer surface of driven cylinder IS. The driven cylinder I8 is thereforewinterlocked with cup 3 by means of the special vane 2|, and thus when, cup 3 is positively rotated, driven cylinder l8 will also be positively rotated.

In Figs. 3 and 4 I have shown the driven cylinder 18 positioned at maximum eccentricity from cup 3 by rotation of driven cylinder shaft IE to provide maximum output. This position can be obtained by rotation of an outside handle 30 attached to shaft l6. Shaft I6 is provided with a pointer 3| operating over a scale .32 mounted on end plate H of the variable displacement pump. Under these conditions, as shaft 5 is rotated counter clockwise (Fig. 3), with. maximum eccentricity of eccentric II, it will be seen that the device acts as a pump, with maximum output, with inlet port l2 receiving fluid and the exhaust port N delivering fluid. When, however, shaft I6 is rotated 180 the condition shown in Fig. 5 is produced, where the driven cylinder 18 is concentric with cup 3, and no pumping will be accomplished.

All gradations of output may be obtained without changing the speed of rotation of shaft 5. from maximum to minimum displacement, by rotation of shaft I'6 over 180'.

While the variable displacement pump of my invention may be utilized by itself, I have indicated one practical manner in which the pump may be utilized, and that is by attachment to' a main flow pump giving a liquid fiow of at least as large an amount as can behandled by the variable displacement pump. manner-of attaching the flow channels of one pump to the other will be immediately apparent to those skilled in the art. Mechanical connection has already been shown in Fig. 1.

Preferably, pump 6 is provided with a by-pass connection between inlet and outlet, so that excess liquid delivered by the outlet of pump 6 can be returned to the inlet. The outlet of pump 6 is then led to the inlet of the variable displacement pump. The variable displacement pump will then supply liquid in accordance with the relative position of cup and cylinder, this position being regulated by turning handle 30 and shaft l6. Such a dual pump is ideal for the supply of fuel to an oil burner, for example, where it is desired to regulate the strength of the flame.

Under these conditions, shaft 1 of pump 6 may be driven by a constant speed motor, and the amount of output from the combined pumps may be regulated at will andwith ease, without shutdown.

I claim:

1. A variable displacement pump comprising a casing having end walls, a drive'shaft entering said casing through one of said end walls, a cup shaped rotor having sidewalls and base fitting said casing and driven by said shaft, a second shaft entering the end of saidcasing which is opposite said drive shaft and having the axis The customary thereof parallel and spaced from the axis of said first shaft, an eccentric mounted on said second shaft and extending into the chamber defined by said cup and one of said casing end 5 walls, the axis of said eccentric being in one position coaxial with said first shaft, a cup-shaped driven member of smaller diameter than said rotor chamber mounted to rotate on said eccentric with the base of said driven member in contact 10 with the base of said rotor, vanes radially mounted in said driven member. and movable to v bear on the inner surface of the side walls of said cup, one of said vanes interlocking with said side walls, resilient'means within the hollow of said driven member forcing said vanes outwardly against said side walls, and inlet and outlet ports oppositely opening into the space between said side walls and said driven member.

2 A variable displacement pump comprising a casing having end walls, a drive shaft entering said casing through one of said end walls, a cup shaped rotor having side walls and base fitting said casing and driven by said shaft, a second shaft entering the end of said casing which is opposite said drive shaft and having the axis thereof parallel and spaced from the axis of said first shaft, an eccentric mounted on said second shaft and extending into the chamber defined by said cup and one of said casing end walls, the axis of said eccentric being in one position coaxial with said first shaft, a cup-shaped driven member of smaller diameter than said rotor chamber mounted to .rotate on said eccentric with the base of said driven member in contact with the base of said rotor, vanes radially mounted in said driven member and movable to bear on the inner surface of the side walls of said cup. one of said vanes interlocking with said side walls, resilient means within the hollow of said driven member forcing said vanes outwardly against said side walls, inlet and outlet ports oppositely opening into the space between said side walls and said driven member, and means for rotating the second shaft over an arc to change the relative axial positions of said rotor and said driven member.

3. Apparatus in accordance with claim 2, wherein said resilient means is a resilient ring bearing on all of said vanes to force them outwardly, the outer edges of said ring, the side wall edges of said rotor, and the side wall edges of said driven member, bearing against said casing adjacent said second shaft entrance therethrough. V 4. Apparatus in accordance with claim 1 wherein means are provided for rotating said second shaft over an arc of 180 to change the relative position of said rotor and said driven member from coaxial position of said eccentric to maximum eccentricity.

5. Apparatus in accordance with claim 2, wherein said casing is cup-shaped and wherein the cup-shaped rotor and cup-shaped driven member are inserted in said casing with the open ends of said rotor and said driven member bearing against the inner basal surface of the cupshaped casing.

ALBERT J. GRANBERG. 

